Computational Study of Heat Transfer to the Walls of a DI Diesel Engine

Payri, F.; Margot, Xandra; Gil, Antonio; Martín, Javier Rodríguez

doi:10.4271/2005-01-0210

Cited by 49 publications

(41 citation statements)

References 9 publications

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“…were set by means of CFD calculations in two previous works developed in the research group [38,39]. Hence, the only value that must be adjusted to have a complete convective HT model in the chamber is the value of , from which is obtained assuming the stated ratio between them.…”

Section: Convective Heat Transfer In the Chambermentioning

confidence: 99%

A New Tool to Perform Global Energy Balances in DI Diesel Engines

Payri¹,

Olmeda²,

Martín³

et al. 2014

SAE Int. J. Engines

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The generalization of exhaust aftertreatment systems along with the growing awareness about climate change is leading to an increasing importance of the efficiency over other criteria during the design of reciprocating engines. Using experimental and theoretical tools to perform detailed global energy balance (GEB) of the engine is a key issue for assessing the potential of different strategies to reduce consumption. With the objective of improving the analysis of GEB, this paper describes a tool that allows calculating the detailed internal repartition of the fuel energy in DI Diesel engines. Starting from the instantaneous in-cylinder pressure, the tool is able to describe the different energy paths thanks to different submodels for all the relevant subsystems. Hence, the heat transfer from gases to engine walls is obtained with specific convective and radiative models in the chamber and ports; the repartition of the heat flux throughout the engine metal elements towards the oil and coolant is estimated with a lumped capacitance model; finally, the ancillary systems and friction losses are obtained through specific semiempirical submodels. The validation of the tool is performed in a 4-cylinder DI Diesel engine instrumented to perform detailed experimental GEB. Finally, a simple analysis of combined internal and external analysis in the complete engine map shows the effect of operating conditions on each energy term. Thus it is demonstrated the utility of the proposed tool, that complements the experimental heat flow measurements in Diesel engine researches oriented to the reduction of energy consumption.

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Section: Convective Heat Transfer In the Chambermentioning

confidence: 99%

A New Tool to Perform Global Energy Balances in DI Diesel Engines

Payri¹,

Olmeda²,

Martín³

et al. 2014

SAE Int. J. Engines

View full text Add to dashboard Cite

show abstract

“…where C and C 2 are constants whose values are 0.12 and 0.001, c m is the mean piston speed, c u is the instantaneous tangential velocity of the gas in the chamber that was adjusted using CFD calculations [30], p 0 is the pressure during motoring conditions assuming a polytrophic evolution, and finally C W1 and C W2 are constants, whose values were adjusted for each engine by means of a combination of experimental and modelling methodology [31].…”

Section: In-cylinder Pressure Signal Analysismentioning

confidence: 99%

“…Along with these two basic equations, several sub-models: a filling and emptying model was used to calculate the trapped mass [27]; the specific heat of the gas depends on both temperature and composition [28]; blow-by model was based on the evolution of the gas in an isentropic nozzle [26]; the chamber volume deformation due to pressure and inertia was calculated by means of a simple deformation model [29];the heat transfer coefficient in the chamber walls was calculated with a modified Woschnilike model [30]:…”

Section: In-cylinder Pressure Signal Analysismentioning

confidence: 99%

In-cylinder soot radiation heat transfer in direct-injection diesel engines

Benajes

Martín

García

et al. 2015

Energy Conversion and Management

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HIGHLIGHTSOptoelectronic pyrometer provides similar results compared with a conventional method Lower injection pressure results in higher radiation Higher ambient temperature and higher in-cylinder gas density produce higher radiation Larger lift-off length reduces the soot volume fraction and the spectral intensity An increase on swirl number, load and CA50 provide a lower total radiation Lower values of EGR implies a decreased on radiation intensity KEYWORDSSoot; in-cylinder heat transfer; radiation; Optical pyrometer; ABSTRACTThe efficiency and CO 2 are one of the main concerns of automotive manufacturers.There are several strategies under investigation to solve this problem. In the present work, the research effort has been focused on improving knowledge of in-cylinder heat transfer and its impact on engine efficiency. In particular, soot radiation was studied since it can be considered a significant source of the efficiency losses in modern diesel engines. Considering previous studies, the portion of total chemical energy released during combustion lost due to radiation heat transfer varies widely from 0.5 up to 10%, depending on engine parameters and combustion process. Thus, the main objective of this work was to evaluate the amount of energy lost to soot radiation relative to the input fuel chemical energy during the combustion event under different operating conditions in a completely controlled environment provided by an optical engine. Under these simplified conditions, two-color method was applied by using high speed imaging pyrometer with cameras (two dimensional results) and optoelectronic pyrometer (zero dimensional results). Once a detailed comparison between both diagnostics was performed, optoelectronic pyrometer was used to characterize radiant energy losses in a fully instrumented 4-cylinder direct-injection light-duty diesel engine. In particular swirl ratio, EGR and combustion phasing effects on radiation heat transfer were evaluated.

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“…Where C and C 2 are constants whose values are 0.12 and 0.001, c m is the mean piston speed, c u is the instantaneous tangential velocity of the gas in the chamber that was adjusted using CFD calculations [27], p0 is the pressure during motoring conditions assuming a polytrophic evolution, and finally C W1 and C W2 are constants, whose values are adjusted for each engine by means of a combination of experimental and modelling methodology [28].…”

Section: Theoretical Toolsmentioning

confidence: 99%

“…-The heat transfer coefficient in the chamber walls is calculated with a modified Woschni-like model [27]:…”

Section: Theoretical Toolsmentioning

confidence: 99%

An Investigation of Radiation Heat Transfer in a Light-Duty Diesel Engine

Benajes¹,

Martín²,

García³

et al. 2015

SAE Int. J. Engines

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In the last two decades engine research has been mainly focused on reducing pollutant emissions. This fact together with growing awareness about the impacts of climate change are leading to an increase in the importance of thermal efficiency over other criteria in the design of internal combustion engines (ICE). In this framework, the heat transfer to the combustion chamber walls can be considered as one of the main sources of indicated efficiency diminution. In particular, in modern direct-injection diesel engines, the radiation emission from soot particles can constitute a significant component of the efficiency losses. Thus, the main of objective of the current research was to evaluate the amount of energy lost to soot radiation relative to the input fuel chemical energy during the combustion event under several representative engine loads and speeds. Moreover, the current research characterized the impact of different engine operating conditions on radiation heat transfer. For this purpose, a combination of theoretical and experimental tools were used. In particular, soot radiation was quantified with a sensor that uses two-color thermometry along with its corresponding simplified radiation model. Experiments were conducted using a 4-cylinder direct-injection light-duty diesel engine fully instrumented with thermocouples. The goal was to calculate the energy balance of the input fuel chemical energy.Results provide a characterization of radiation heat transfer for different engine loads and speeds as well as radiation trends for different engine operating conditions.

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Computational Study of Heat Transfer to the Walls of a DI Diesel Engine

Cited by 49 publications

References 9 publications

A New Tool to Perform Global Energy Balances in DI Diesel Engines

A New Tool to Perform Global Energy Balances in DI Diesel Engines

In-cylinder soot radiation heat transfer in direct-injection diesel engines

An Investigation of Radiation Heat Transfer in a Light-Duty Diesel Engine

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